Parasitology Flashcards
Ascaris lumbricoides (giant roundworm)
Fecal-oral; eggs visible in feces under microscope (because they’re giant). causes Intestinal infection. Bendazoles or pyrantel pamoate
Enterobius vermicularis (Pinworm)
fecal-oral transmission. Intestinal infection causing anal pruritus (diagnosed via the Scotch Tape test). Bendazoles or pyrantel pamoate (because worms are bendy)
Strongyloides stercoralis
larvae in soil penetrate the skin. Intestinal infection causing vomiting, diarrhea, epigastric pain (may be peptic ulcer- like). Ivermectin or albendazole (STRONG ass roundworm burrowing all the way through skin into intestines and needing ALbendazole/ivermectin vs regular bendazole)
Hookworms (Ancylostoma duodenale, Necator americanus)
Larvae penetrate skin. Intestinal infection causing anemia by sucking blood from intestinal walls. Bendazoles or pyrantel pamoate
What are the intestinal Nematodes?
Enterobius vermicularis (pinworm), Ascaris lumbricoides (giant roundworm), Strongyloides stercoralis, Ancylostoma duodenale/Necator americanus (hookworms)
What are the tissue Nematodes?
Onchocerca volvulus, Loa loa, Wuchereria bancrofti and Toxocara canis
Onchocerca volvulus
female blackfly bite. causes hyperpigmented skin and river blindness (black flies cause black skin and black sight). Treat with IVERmectin (rIVER blindness)
Loa loa
Deer fly, horse fly or mango fly. causes swelling in the skin, worm in conjunctiva. treat with diethylcarbamazine
Wuchereria bancrofti
female mosquito. blocks lymphatic vessels to give elephantitis, which usually happens 9mo-1yr after bite. treat with Diethylcarbamazine
Toxocara canis
fecal-oral route. visceral larva migrans. give albendazole/mebendazole.
Nematode routes of infxn
Ingested: EAT (Enterobius, Ascaris, Toxacara)
Cutaneous: can get these into your feet from SANd (Strongyloides, Ancylostoma, Necator)
Bites: lay LOW to avoid getting bitten (Loa loa, onchocerca, Wuchereria)
Cestodes?
Taenia solium, Diphyllobothrium latum and Echinococcus granulosus
T. solium
ingestion of larvae from undercooked pork; causes intestinal infection; praziquantel
ingestion of eggs from other sources; cysticercosis/neurocysticercosis; praziquantel/albendazole for neurocysti
Diphyllobothrium latum
ingestion of larvae from raw freshwater fish. causes vit. B12 deficiency (by competing for B12 in intestine). treat with praziquantel
Echinococcus granulosus
ingestion of eggs from dog feces. Hydatid cysts in liver, causing anaphylaxis if antigens released (surgeons preinject with ethanol to kill cysts before removal). treat with albendazole before trying surgery.
Trematodes?
Schistosoma and Clonorchis sinesis
Schistosoma haematobium
snails are hosts and they can penetrate human skin. can lead to squamous cell carcinoma of the bladder. treat with praziquantel.
Schistosoma mansoni and japonicum
snails are hosts and can penetrate skin of humans. Cause liver and spleen granulomas/fibrosis leading to eventual portal hypertension. praziquantel.
Clonorchis sinensis
undercooked fish. Biliary tract inflammation causing pigmented gallstones. Associated with cholangiocarcinoma. Praziquantel.
Protozoa_GI
Giardia lamblia, Entamoeba histolytica, cryptosporidium
Protozoa- CNS
Toxoplasma gondii, Naegleria fowleri, Trypanosoma brucei
Protozoa-Heme
Plasmodium (vivax/ovale, falciparum, malariae), Babesia
Protozoa-Other
Visc: Trypanosoma cruzi, Leishmania donovani
STD- Trichomonas vaginalis
Giardia lamblia
Transmission: cysts in water
Diagnosis: trophozites oor cysts in stool
Causes: GIardiasis-bolating, flatulence, fatty diarrhea in campers/hikers. “fatty ghiradelli”
TX: Metronidazole
Entamoeba histolytica
Transmission: Cysts in water
Diagnosis: serology and/or trophozoites (with RBCs in cytoplasm) or cysts with unto 4 nuclei in stool. *histology with flask shaped ulcer
Causes: amebiasis- dysentery, liver abscess (anchovy paste). RUQ pain.
TX:Metronidazole / iodoquinol for asymp cyst passers
cryptosporidium
Transmission: oocytes in water
Diagnosis:oocytes on AF stain
Causes: Severe diarrhea in AIDs. mild in others
TX: Prevention with filtering water. nitazoxanide in i-competent hosts
Toxoplasma gondii
Transmission: cysts in meat (mostly); oocytes in cat feces crosses placenta (preggers avoid cats)
Diagnosis:
Causes: congenital =chroioretinitis, hydrocephalus, IC calcifications. reactivation in AIDs-> brain abscess seen in ring enhacning CT/MRI
TX:Sulfadiazine + pyrimethamine
Naegleria fowler
Transmission:swimming in freshwater lakes ( like nalgene bottle filled with fresh water)-> cribiform plate entry
Diagnosis: amoebas in spinal tap
Causes: rapidly fatal meningoencephalitis
TX:Amp B for few survivors
Trypanosoma brucei
Transmission: tsetse fly, painful bite
Diagnosis: blood smear
Causes: African sleeping sickness-enlarhed LNs, recurring fever (antigenic variation) somnolence, coma
sub-species: T b. rhodesiense, T b. gambiense
TX: Suramin for blood borne, melarsoprol for CNS penetration.
Plasmodium (vivax/ovale)
Transmission:Anopheles mosquito
Diagnosis: Blood smear with trophozoite ring within RBC, schizont containing merozoites, ** red granules (schuffner stippling) though out RBC
Causes: 48 hr cycle tertian fever, w/ efevrs 1st/3rd day; dormant hypozoite in liver
TX:Cholroquine for sensitive blocks plasmodium heme polymerase. for res use mefloquine or atovaquone/proguanil. life threatening use IV quinidine or artesunate (test for G6PD first); ** for vivax use primaquine for hypozoite (test G6PD)
Plasmodium (falciparum)
Transmission:Anopheles mosquito
Diagnosis: Blood smear with trophozoite ring within RBC, schizont containing merozoites
Causes: severe, irregular fevers; parasitized RBCs occlude capillaries in brain ( cerebral malaria), kidneys, lungs
TX:Cholroquine for sensitive blocks plasmodium heme polymerase. for res use mefloquine or atovaquone/proguanil. life threatening use IV quinidine or artesunate (test for G6PD first)
Plasmodium (malariae)
Transmission:Anopheles mosquito
Diagnosis: Blood smear with trophozoite ring within RBC, schizont containing merozoites, rC
Causes: 72 hr cycle (quartan)
TX:Cholroquine for sensitive blocks plasmodium heme polymerase. for res use mefloquine or atovaquone/proguanil. life threatening use IV quinidine or artesunate (test for G6PD first)
Trypanosoma cruzi,
Transmission: Reduvid bug (“kissing bug” or feces depositied in painless bite.
Diagnosis:blood smear
Causes: Chagas disease -dilated cardiomyopathy, apical atrophy, megacolon, megaesophagus; predom SAmerica. Unilateral peri-orbital swelling (Romana sign) characterizes acute stage.
TX: Benznidazole or nifutimox
Leishmania donovani
Transmission: Sandfly
Diagnosis: Mecrophages containing amastogotes
Causes: Visc leishmaniasis (kala-azar)-spiking fevers, HSMegaly, pancytopenia.
TX: Amp B, sodium stibogluconate
Trichomonas vaginalis
Transmission: sexual-cannot exist outside body as cannot form cysts
Diagnosis: trophozoites on wet mount; strawberry cervix
Causes: Vaginitis= foul smelling, greenish dischrge +itching/burning
TX: metronidazole (& partner Ppx)
